Recently a set of theories has evolved which permits identification of a large class of nonlinear systems. An NIH Research Grant was recently made to me to apply these methods to the study of retinal biopotentials, specifically the human ERG. This work is progressing well and we have high hopes that the nonlinear analysis of the ERG will be a powerful clinical tool. The nonlinear technique involves stimulating the eye with a steady background illumination on which is superimposed a quasi-random modulation of intensity. The ERG waveform elicited by this stimulus is recorded and the nonlinear analysis is performed by high-order cross-correlation techniques between the input waveform and the recorded waveform. Currently, the only means for computing the second-order and high-order cross-correlations involves a large computing facility and considerable interfacing costs. A quasi-random light modulator is also not readily available. These facts, if left unchanged, will act as considerable deterrants to the adoption of these new techniques in clinical practice. We have built a compact and trouble-free stimulator, and a special purpose computer system that will perform the nonlinear analysis and display the results in real-time. The equipment is designed around a microprocessor so that modifications can be made by reprogramming. Our goal now is to evaluate this equipment in collaboration with research clinicians and to subject it to preliminary clinical tests.